Yitzhak Cohen was riding on the bus when the blast occurred at 0715 local time (0515 GMT), during the morning rush hour.

"Suddenly there was a huge explosion. Something fell on my head and I fell to the floor. Around me there were bodies everywhere, some of them lying one on top of the other," he told the Reuters news agency.

Forceful blast

The force of the blast splattered blood and human remains on a wall some 30 metres (100 feet) from the explosion.

Nearly 50 were injured

The ground around the ruined bus was littered with schoolbooks and sandwiches.

"I've lived in this neighbourhood for 42-years and I'm waiting to see how many of my friends are dead," resident Meir Ohayon told AFP.

The body of the bomber - believed to be a man in his early 20s who entered Jerusalem from Bethlehem - was so mangled in the explosion that police were initially unable to say if he was carrying the bomb in a bag or if it was strapped to his body.

The attack on Thursday was the first fatal bombing in Jerusalem since 31 July, when seven people were killed at the Hebrew University. It is the deadliest since June 18, when 19 civilians died in a suicide attack.

Palestinian militants have been carrying out a campaign of suicide bombings - which human rights groups have condemned as war crimes - and other attacks on Israeli targets during their two-year-old uprising.